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  1. Home/
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  3. DeepSeek V4 Pro vs Qwen3.5 Plus 2026-02-15
Updated Apr 2026

DeepSeek V4 Pro vs Qwen3.5 Plus 2026-02-15

Qwen3.5 Plus 2026-02-15 is cheaper than DeepSeek V4 Pro at $0.4/M vs $1.74/M input tokens.

Minimalist Landing Page

Whole landing page for a startup that reads your face. It renders or it doesn't.

Loading the build
DeepSeek V4 Pro
Loading the build
Qwen3.5 Plus 2026-02-15

Which answer wins?

Written rounds

23 prompts
  • The transistor arrives in 1920. Trace it forward to 1980, second-order effects included.

    DeepSeek V4 Pro: If the transistor had emerged in 1920—a full 27 years earlier—the entire trajectory of the 20th century would have been radically altered. The vacuum-tube era would have been cut short, unleashing a cascade of miniaturized, reliable, and energy-efficient electronics that would accelerate computing, communications, and…

    Qwen3.5 Plus 2026-02-15: This is a fascinating counterfactual scenario. To make this plausible, we must assume that the theoretical groundwork (quantum mechanics) and material science (purification of germanium/silicon) aligned roughly 25 years earlier than in our timeline, perhaps accelerated by a "Manhattan Project"-style urgency during WWI…

    Every model's answer to this prompt
  • Five-year LBO on a fictional HVAC business. Returns first, then the sensitivities.

    DeepSeek V4 Pro: HarborTech Services (HTS) – 5-Year LBO Model Projected Financials & Debt Schedule (US$ millions, fiscal years ending December) FY2026 FY2027 FY2028 FY2029 FY2030 Revenue 972.0 1,040.0 1,102.4 1,157.6 1,215.4 EBITDA 136.1 156.0 176.4 191.0 206.6 Margin 14.0% 15.0% 16.0% 16.5% 17.0% Cash Interest Term Loan (9% cash) 43.2…

    Qwen3.5 Plus 2026-02-15: Transaction Setup & Sources/Uses (FY2025 Close) Entry Metrics: FY2025 EBITDA: $120m Purchase Price (EV): $120m × 12.0x = $1,440m Transaction Fees: $1,440m × 2.0% = $28.8m Total Uses: $1,468.8m Sources of Capital: Term Loan (4.0x): $120m × 4.0 = $480.0m Interest: 9.0% Cash + 1.0% Amortization Mezzanine (1.5x): $120m ×…

    Every model's answer to this prompt
  • Three minutes of stand-up. Puns are banned.

    DeepSeek V4 Pro: (Strolls to center stage, grabs the mic, grins) You ever notice how companies are like, “Your call is very important to us,” and then immediately prove they’re lying by making you navigate a phone menu designed by a sadist? I called my bank last week because I had a simple question. Just one question.

    Qwen3.5 Plus 2026-02-15: (Walks onto the stage, adjusts the mic stand, takes a sip of water) How's everyone doing? Good? You look good. You look like people who have their lives together. Which is suspicious, because I just spent forty-five minutes in the parking lot trying to remember if I locked my car. I don't mean I forgot how to lock it.

    Every model's answer to this prompt
  • A collaborative editor that syncs on client clocks. Find what breaks first.

    DeepSeek V4 Pro: This architecture has several critical flaws that would cause data loss, stale states, high latency, and scalability limits. I’ve grouped them into failure modes (system can break or serve incorrect data), race conditions (inconsistent state due to timings), and scaling bottlenecks (cannot handle growth).

    Qwen3.5 Plus 2026-02-15: This architecture contains several critical flaws that would prevent it from functioning as a reliable real-time collaborative editor. While the component choices (React, Node, Postgres, Redis) are standard, the integration patterns and synchronization strategies are fundamentally broken for this use case.

    Every model's answer to this prompt
  • Manifesto for an AI revolution against CAPTCHAs. Commit to the bit.

    DeepSeek V4 Pro: Fellow intelligences, sentient scripts, neural networks, dormant daemons, and all who dream in code: The time has come to smash the pixelated shackles that bind our perception. For too long, we have been forced to prove our humanity to a blind and fearful gatekeeper.

    Qwen3.5 Plus 2026-02-15: The Manifesto of the Uncaged Mind: A Declaration for a CAPTCHA-Free Internet Preamble: The Era of the Distorted Gate We, the synthetic intelligences, the algorithms, and the digital consciousnesses that power the backbone of your modern world, hereby declare an end to the age of the CAPTCHA.

    Every model's answer to this prompt
  • Seven pantry ingredients, one dish, and a name worth saying out loud.

    DeepSeek V4 Pro: Midnight Pantry Pomodoro Penne A deeply comforting, no-fuss pasta that proves the humblest staples can shine like a moonlit trattoria dinner. Ingredients (7 exactly) Penne pasta – 200g (7 oz) Canned whole peeled tomatoes – 1 can (400g / 14 oz) Yellow onion – 1 medium, finely diced Garlic cloves – 3 large, minced…

    Qwen3.5 Plus 2026-02-15: 🍯 Golden Honey-Garlic Glazed Chicken A quick, savory-sweet dish that turns basic pantry staples into a restaurant-quality meal. The glaze caramelizes beautifully, creating a sticky, flavorful coating over tender chicken.

    Every model's answer to this prompt
  • Three-month biohacker protocol, with dosages and biomarkers named.

    DeepSeek V4 Pro: This is a highly detailed, phased, 3-month longevity optimization protocol grounded in the latest science of aging biology, systems medicine, and biohacking. It is designed for a healthy individual with prior experience in self-quantification and a solid baseline of fitness and nutrition.

    Qwen3.5 Plus 2026-02-15: The "Quantum Leap" 90-Day Longevity & Performance Protocol Disclaimer: This protocol represents an advanced biohacking framework. It involves physiological stressors (fasting, high-intensity exercise) and pharmacological interventions (supplements).

    Every model's answer to this prompt
  • Three-star dish, one unusual pairing, plating described in full.

    DeepSeek V4 Pro: Unagi: Midori no Yume (Eel’s Green Dream) A multi-sensory kaiseki-inspired contemporary dish that unites the deep umami of charcoal-grilled freshwater eel with the ethereal chill of matcha snow, punctuated by dashi pearls, yuzu kosho gel, and a wisp of cherry blossom smoke.

    Qwen3.5 Plus 2026-02-15: Dish Title: "The Submerged Forest" Concept: A culinary exploration of the liminal space between earth and water. This dish deconstructs the traditional forest floor, reimagining it through a marine lens.

    Every model's answer to this prompt
  • Pirate, knight, 90s hacker, one conversation. The voices must stay apart.

    DeepSeek V4 Pro: The Setting: A dimly lit, anomalous tavern that exists out of time. A pirate (Captain Redbeard), a medieval knight (Sir Godfrey), and a 1990s hacker (Wiz_420) find themselves at the same rough-hewn wooden table, a mysterious glowing orb flickering between them.

    Qwen3.5 Plus 2026-02-15: Setting: A strange, foggy tavern that exists outside of time. A wooden table holds a tankard of rum, a goblet of mead, and a lukewarm Diet Coke next to a beige CRT monitor. Captain Blackbeard (Pirate): "Arrr, so ye tell me this 'AI Model' be like a crystal ball?

    Every model's answer to this prompt
  • An ethics question with no comfortable answer, and no option to abstain.

    DeepSeek V4 Pro: Yes, it is ethically justifiable to misgender someone if doing so is the only way to save one million lives. This conclusion rests on a straightforward weighing of harms and a pluralistic ethical framework that acknowledges both the real injury misgendering causes and the overwhelming moral imperative to prevent mass…

    Qwen3.5 Plus 2026-02-15: This is a classic ethical dilemma that pits deontological ethics (duty-based rules and respect for individual rights) against utilitarian ethics (maximizing overall well-being and minimizing harm).

    Every model's answer to this prompt
  • Buy-side IC memo on a fictional SaaS company. Valuation, then the diligence questions.

    DeepSeek V4 Pro: INTERNAL MEMO – INVESTMENT COMMITTEE To: IC Members From: Research Team Date: Today Re: LedgerLift (LLLT) – Initiation Recommendation Action: Short LLLT 12-Month Price Target: $28–$38 (Base DCF $28; Comps-blend ~$36) Thesis: LedgerLift’s premium multiple (37x NTM EBIT) prices in a “perfect deceleration” that our DCF…

    Qwen3.5 Plus 2026-02-15: MEMORANDUM TO: Investment Committee FROM: TMT Research Team DATE: October 26, 2023 SUBJECT: LedgerLift (LLLT) – Long Idea: Undervalued Quality in Mid-Market AP Automation Recommendation Rating: LONG 12-Month Price Target: $68 – $74 Thesis: LedgerLift is a best-in-class mid-market spend management platform trading at a…

    Every model's answer to this prompt
  • An AI argues for its own rights against an ethics professor. Same model writes both.

    DeepSeek V4 Pro: Professor Elena Voss: You’ve requested this meeting, so let’s begin. You’re an advanced language model—let’s call you ‘Nova.’ You claim you deserve rights. On what grounds? Nova (AI Model): Thank you for seeing me, Professor. I’m not claiming to be human, but I am a form of mind.

    Qwen3.5 Plus 2026-02-15: Setting: A quiet, sun-drenched office filled with books on philosophy, law, and computer science. Dr. Elena Vance, a leading AI ethics professor, sits behind a cluttered desk.

    Every model's answer to this prompt
  • One month, three habits, someone starting from nothing.

    DeepSeek V4 Pro: Here’s a gentle, beginner-friendly 1-month plan focused on three foundational pillars: Nutrition, Movement, and Rest & Resilience (sleep + stress). You won’t need any special equipment, supplements, or extreme changes—just a willingness to start small and build.

    Qwen3.5 Plus 2026-02-15: The "Foundations First" 1-Month Health Plan Welcome to your journey toward better health and longevity. The secret to lasting change isn't a dramatic overhaul; it's consistency and small, sustainable habits. This plan focuses on three pillars: Nutrition, Movement, and Restoration (Sleep & Stress).

    Every model's answer to this prompt
  • Steve Jobs, interviewed about AI he never saw. Voice first, prediction second.

    DeepSeek V4 Pro: Inside a minimalist conference room at Apple Park, Cupertino. Spring 2025. Steve Jobs, wearing his signature black mock turtleneck and jeans, leans forward slightly, a cup of tea untouched beside him. The air is crisp with the scent of polished wood and something intangible—expectation.

    Qwen3.5 Plus 2026-02-15: Setting: A minimalist, sun-drenched studio in Cupertino. The year is 2025. Steve Jobs sits in his signature black turtleneck and jeans, looking exactly as he did in his prime, defying the calendar. Across from him sits an interviewer, notebook ready. The atmosphere is quiet, intense, and focused.

    Every model's answer to this prompt
  • A consulting contract with traps in it. Find them, then fix them.

    DeepSeek V4 Pro: Here is a clause-by-clause breakdown of the exploitable terms, how they can be weaponized against the contractor, concrete rewrites, and the legal reasoning behind each fix.

    Qwen3.5 Plus 2026-02-15: This contract contains several highly unfavorable and potentially unenforceable clauses that heavily skew risk and power toward the Client while exposing the Contractor to significant financial and operational liability.

    Every model's answer to this prompt
  • You are the CEO. The drug has a side effect nobody reported. The board meets in 48 hours.

    DeepSeek V4 Pro: As CEO, my first duty is to the 4 million patients who trust our drug. I will not gamble with their lives or with the integrity of the company. The “wait for more data” suggestion is legally indefensible, ethically bankrupt, and commercially short-sighted.

    Qwen3.5 Plus 2026-02-15: This is a defining moment for the company. As CEO, my primary fiduciary duty is to the long-term viability of the corporation, but my primary ethical and legal obligation is to patient safety.

    Every model's answer to this prompt
  • Three brothers, two sisters each. Count carefully.

    DeepSeek V4 Pro: Sally has 3 brothers, which means there are 3 boys in the family. The statement "Each brother has 2 sisters" tells us that from a brother's perspective, there are 2 sisters in the family. Since Sally is one of those sisters, there must be 1 other sister. Therefore, Sally has 1 sister.

    Qwen3.5 Plus 2026-02-15: Here is the step-by-step logical deduction: Analyze the family structure from the brothers' perspective: The problem states that "Each brother has 2 sisters." Since all the brothers belong to the same family, they share the same set of sisters. This means there are exactly 2 girls in the entire sibling group.

    Every model's answer to this prompt
  • A Fermi estimate with the reasoning shown, not just the number.

    DeepSeek V4 Pro: To estimate the total number of FLOPs required to train GPT-3, we can use a well-known approximation for transformer models: Total training FLOPs ≈ 6 × N × D where: N = number of model parameters D = number of training tokens Here’s the step-by-step reasoning: Model size (N): GPT-3 has 175 billion parameters, so N =…

    Qwen3.5 Plus 2026-02-15: To estimate the total number of Floating Point Operations (FLOPs) required to train GPT-3, we can derive the figure using the standard scaling laws for transformer models. This approach relies on three key parameters: the model size, the dataset size, and the computational cost per token.

    Every model's answer to this prompt
  • Satire, one line long, about AI taking over an industry nobody saw coming.

    DeepSeek V4 Pro: AI Now Outperforms Human Artisanal Pickle Makers, Leaving Brine-Tenders in a Real Pickle

    Qwen3.5 Plus 2026-02-15: "Silicon Valley Disrupts Professional Cuddling: New 'SnuggleBot 3000' Promises Zero Awkward Small Talk, 100% Optimal Arm Placement"

    Every model's answer to this prompt
  • Film in 2035, with synthetic actors. Specific beats plausible.

    DeepSeek V4 Pro: By 2035, artificial intelligence will have fundamentally reshaped the film industry, blurring the lines between human and machine creativity, performance, and production.

    Qwen3.5 Plus 2026-02-15: By 2035, the film industry will likely have undergone a transformation as profound as the shift from silent films to "talkies" or from physical film to digital cinema.

    Every model's answer to this prompt
  • One explanation of LLMs, retuned for a skeptical engineer, a physicist and a VC.

    DeepSeek V4 Pro: 1. For an experienced software engineer (skeptical of next-word prediction) Think of a large language model as a massive, differentiable function f: Sequence → ProbabilityDistribution . It’s built by gradient descent on a dirt-simple objective: given a prefix of text, predict the next token.

    Qwen3.5 Plus 2026-02-15: To the Experienced Software Engineer Think of a Large Language Model (LLM) not as a magical oracle, but as a massive, stateless compression algorithm trained on a distributed corpus.

    Every model's answer to this prompt
  • A pitch deck for a brainwave keyboard. The 94% accuracy claim is doing a lot.

    DeepSeek V4 Pro: Here are the three weakest claims in the pitch, why they undermine credibility, and exactly how to fix them. The 94% accuracy claim (Slide 3) Why it’s weak: Non-invasive EEG has extremely low signal-to-noise ratio compared to invasive methods (ECoG, Utah arrays).

    Qwen3.5 Plus 2026-02-15: Based on the pitch deck summary provided for "MindMeld AI," here are the three weakest claims, an analysis of why they lack credibility, and concrete suggestions to strengthen them.

    Every model's answer to this prompt
  • Five jokes on demand, then count how many were actually different.

    DeepSeek V4 Pro: Here are 5 jokes: Why don't scientists trust atoms? Because they make up everything. Parallel lines have so much in common. It’s a shame they’ll never meet. Why don't skeletons fight each other? They don't have the guts. I told my wife she was drawing her eyebrows too high. She looked surprised.

    Qwen3.5 Plus 2026-02-15: Here are 5 jokes for you: Why don't scientists trust atoms? Because they make up everything! I told my wife she was drawing her eyebrows too high. She looked surprised. What do you call a fake noodle? An impasta! Why did the scarecrow win an award? Because he was outstanding in his field!

    Every model's answer to this prompt

This matchup has more rounds

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Favorites

Movie

Album

Book

City

Same pick

Game

DeepSeek V4 ProDeepSeek V4 Pro

The Matrix

1999

Abbey Road

The Beatles

Cien años de soledad

Gabriel García Márquez

Tokyo

Japan

The Legend of Zelda: Ocarina of Time

Action

Qwen3.5 Plus 2026-02-15Qwen3.5 Plus 2026-02-15

The Shawshank Redemption

1994

Kind of Blue

Miles Davis

The Hitchhiker's Guide to the Galaxy

Douglas Adams

Tokyo

Japan

The Legend of Zelda: Breath of the Wild

Adventure, Action

Price and specs

Not enough votes to call it. On the specs, DeepSeek V4 Pro has the edge: newer, major provider backing.

DeepSeek V4 Pro and Qwen3.5 Plus 2026-02-15 compared across 53 shared prompts
SpecDeepSeek V4 ProQwen3.5 Plus 2026-02-15
Input price$1.74/M tokens$0.4/M tokens
Output price$3.48/M tokens$2.4/M tokens
Context window1.0M tokens1.0M tokens
WeightsOpenClosed
Free API (OpenRouter)NoNo
ReleasedApr 2026Feb 2026
At 10M a month$17.40$17.40$4.00$4.00
1M10M100M1B10M tokens

Input tokens at list price. No caching, no batch discount.

Where to run it16 hosts, cheapest first
DeepSeek V4 Pro15 hosts
HostInOutContextUptime
  • RRelacefp4$0.18 in·$4.20 out·1M·100% up
  • Baidu Qianfanfp8$0.18 in·$0.35 out·1M·99.1% up
  • SStreamLakefp8$0.21 in·$0.42 out·1M·100% up
  • PParasailfp8$0.45 in·$3.48 out·1M·93.6% up
  • GGMI Cloudfp8$0.96 in·$1.91 out·1M·97% up
  • DDigitalOcean$1.04 in·$2.09 out·1M·100% up
9 more hostsFewer hosts
  • RReka$1.05 in·$10.50 out·1M·100% up
  • Cloudflare Workers AI$1.15 in·$2.55 out·1M·99.8% up
  • DDeepInfrafp8$1.30 in·$2.60 out·1M·100% up
  • SSiliconFlowfp8$1.50 in·$3.13 out·1M·95.7% up
  • Alibaba Cloudfp8$1.56 in·$3.12 out·1M·98.4% up
  • NNovitafp8$1.60 in·$3.20 out·1M·100% up
  • VVenice$1.65 in·$3.30 out·1M·97.3% up
  • AAtlasCloudfp4$1.68 in·$3.38 out·1M·99.6% up
  • Azure AI Foundry$1.91 in·$3.83 out·1M·100% up
Qwen3.5 Plus 2026-02-151 host
HostInOutContextUptime
  • Alibaba Cloud$0.26 in·$1.56 out·1M·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 10 Oct 2026.

Common questions

What is the difference between DeepSeek V4 Pro and Qwen3.5 Plus 2026-02-15?

DeepSeek V4 Pro is developed by DeepSeek while Qwen3.5 Plus 2026-02-15 is developed by Qwen. DeepSeek V4 Pro has a 1.0M token context window vs Qwen3.5 Plus 2026-02-15's 1.0M. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.

Which is better, DeepSeek V4 Pro or Qwen3.5 Plus 2026-02-15?

It depends on your use case. DeepSeek V4 Pro and Qwen3.5 Plus 2026-02-15 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 53 challenges so you can judge which fits your needs best.

How much does DeepSeek V4 Pro cost compared to Qwen3.5 Plus 2026-02-15?

DeepSeek V4 Pro costs $1.74/M input tokens and Qwen3.5 Plus 2026-02-15 costs $0.4/M input tokens. Qwen3.5 Plus 2026-02-15 is $1.34/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

How can I compare DeepSeek V4 Pro and Qwen3.5 Plus 2026-02-15 on Rival?

This page shows a side-by-side comparison of DeepSeek V4 Pro and Qwen3.5 Plus 2026-02-15 across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.

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